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Abstract

A description of direct simulation of crosswind loads caused by critical vortex excitation and the response of the structure to these loads are presented in this paper. Tower-like structures of circular cross-sections are considered. A proposed mathematical model of vortex excitation has been numerically implemented and a selfserving computer program was created for the purpose. This software, cooperating with the FEM system, allows for a simulation of a crosswind load and lateral response in real time, meaning that at each time step of the calculations the load is generated using information regarding displacements seen beforehand. A detailed description of the mathematical model is neglected in this paper, which is focused on numerical simulations. WAWS and AR methods are used in simulations.

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Authors and Affiliations

T. Lipecki
A. Flaga
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Abstract

The work concerns dynamic similarity criteria of various phenomena occurring in hydraulics and fluid dynamics originally derived from ratios of forces and forces moments affecting these phenomena. The base of dynamic similarity criteria formulations and considerations is A. Flaga’s method and procedure for determining dynamic similarity criteria in different issues of fluid–solid interactions i.e. at different fluid–solid relative motions. The paper concerns the determination and analysis of dynamic similarity criteria for various practical problems encountered mainly in hydraulics and fluid dynamics at steady, smooth fluid onflow in front of a solid. Moreover, the cases of mechanically induced vibrations of a body in a stationary fluid moving with constant velocity in front of the body have been presented. Assuming authorial method and procedure for determining dynamic similarity criteria, its have been presented and analysed in the paper both well known similarity numbers obtained in another way (e.g. from dimensional analysis or differential equations for particular problems – as Reynolds, Froude, Euler, Cauchy, Strouhal, Mach numbers) – as well as several new similarity numbers encountered in different fluid solid interaction problems (e.g. new forces and moments coefficients encountered in problems of vibrating solid bodies in fluids).
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Authors and Affiliations

Andrzej Flaga
1
ORCID: ORCID
Renata Kłaput
1
ORCID: ORCID
Łukasz Flaga
1
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Civil Engineering, Wind Engineering Laboratory, Jana Pawła II 37/3a, 31-864 Cracow, Poland
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Abstract

The subject of the wind tunnel tests is a steel chimney 85 m high of cylindrical – type structure with a grid-type curtain structure situated at its upper part. The model of the upper part of the chimney made in the scale of 1:19 was equipped with 3 levels of wind pressure measurement points. Each level contained 24 points connected with pressure scanners. On the base of the pressure measurements, both mean and instantaneous aerodynamic drag and side force coefficients were determined. Next wind gust factors for these two wind action components were determined. Moreover, for each pressure signal Fast Fourier Transform was done. Mean wind action components were also determined using stain gauge aerodynamic balance. Obtained results make possible to conclude that the solution applied in the upper part of the designed chimney is correct from building aerodynamics point of view. Some minor vortex excitations were observed during model tests of the upper part of the chimney. The basic dynamic excitation of this part of the chimney is atmospheric turbulence.
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Bibliography



[1] Zdravkovich M.M., “Review and classification oof various aerodynamic and hydrodynamic means for suppressing vortex shedding”. J.Wind Eng. Ind. Aerodyn., 7(2): pp. 145-189, 1981.
[2] Arunachalam, S., & Lakshmanan, N. (2015). “Across-wind response of tall circular chimneys to vortex shedding”. Journal of Wind Engineering and Industrial Aerodynamics, 145, pp. 187–195, https://doi.org/10.1016/j.jweia.2015.06.005.
[3] Wang, L., & Fan, X. (2019). “Failure cases of high chimneys: A review”. Engineering Failure Analysis, 105, pp. 1107–1117, https://doi.org/10.1016/j.engfailanal.2019.07.032.
[4] Vickery, B. J., & Basu, R. I., “The response of reinforced concrete chimneys to vortex shedding”. Engineering Structures, 6(4), pp. 324–333, 1974
[5] Flaga A., “Wind vortex-induced excitation and vibration of slender structures-single structure of circular cross-section normal to flow”. Monograph No. 202. Cracow University of Technology, Cracow 1996.
[6] Lipecki, T., & Flaga, A. (2013). “Vortex excitation model. Part I. mathematical description and numerical implementation”. Wind and Structures, 16(5), pp. 457–476.
[7] Lipecki, T., & Flaga, A. (2013). “Vortex excitation model. Part II. application to real structures and validation”. Wind and Structures, 16(5), pp. 477–490, https://doi.org/10.12989/was.2013.16.5.477.
[8] Brownjohn, J. M. W., Carden, E. P., Goddard, C. R., & Oudin, G. (2010). “Real-time performance monitoring of tuned mass damper system for a 183 m reinforced concrete chimney”. Journal of Wind Engineering and Industrial Aerodynamics, 98(3), pp. 169–179, https://doi.org/10.1016/j.jweia.2009.10.013.
[9] Christensen, R. M., Nielsen, M. G., & Støttrup-Andersen, U. (2017). “Effective vibration dampers for masts, towers and chimneys”. Steel Construction, 10(3), pp. 234–240, https://doi.org/10.1002/stco.201710032.
[10] Belver, A. V., Ibán, A. L., & Lavín Martín, C. E. (2012). “Coupling between structural and fluid dynamic problems applied to vortex shedding in a 90m steel chimney”. Journal of Wind Engineering and Industrial Aerodynamics, 100(1), pp. 30–37. .
[11] Verboom, G. K., & van Koten, H. (2010). “Vortex excitation: Three design rules tested on 13 industrial chimneys”. Journal of Wind Engineering and Industrial Aerodynamics, 98(3), pp. 145–154, https://doi.org/10.1016/j.jweia.2009.10.008.
[12] Kawecki, J., & Żurański, J. A. (2007). ”Cross-wind vibrations of steel chimneys – A new case history”. Journal of Wind Engineering and Industrial Aerodynamics, 95(9–11), pp. 1166–1175.
[13] Lupi, F., Höffer, R., & Niemann, H.-J. (2021). “Aerodynamic damping in vortex resonance from aeroelastic wind tunnel tests on a stack”. Journal of Wind Engineering and Industrial Aerodynamics, 208, pp. 104–438.
[14] Lupi, F., Niemann, H.-J., & Höffer, R. (2017). “A novel spectral method for cross-wind vibrations: Application to 27 full-scale chimneys”. Journal of Wind Engineering and Industrial Aerodynamics, 171, pp. 353–365, https://doi.org/10.1016/j.jweia.2017.10.014.
[15] Rahman, S., Jain, A. K., Bharti, S. D., & Datta, T. K. (2020). “Comparison of international wind codes for across wind response of concrete chimneys”. Journal of Wind Engineering and Industrial Aerodynamics, 207, pp. 104–401.
[16] Ruscheweyh H., “Dynamische Windwirkung an Bauwerken. Band 2: Praktische Anwendungen. Bauverlag”. Wiesbaden und Berlin, 1982.
[17] Blevins R.D., “Flow-induced vibration. Second edition”. Van Nostrand Reinhold, New York 1990.
[18] Flaga A., “Wind engineering – fundamentals and applications” (in Polish), Arkady, Warsaw (2008).
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Authors and Affiliations

Andrzej Flaga
1
ORCID: ORCID
Renata Kłaput
1
ORCID: ORCID
Łukasz Flaga
1
ORCID: ORCID
Piotr Krajewski
1
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Civil Engineering, Wind Engineering Laboratory, Jana Pawła II 37/3a, 31-864 Cracow
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Abstract

The aim of the study was to determine the utility of maximum eye temperature measured by infrared thermography (IRT) as a stress indicator compared with plasma cortisol concentration in Thoroughbred and Arabian racehorses. The study included thirty racehorses undergoing standard training for racing. Measurements of maximum eye temperature and blood collection for plasma cortisol concentration were carried out before training (BT), and within 5 (5AT) and 120 minutes (120AT) after the end of the each training session in three repetitions, with a monthly interval. Both parameters were elevated at 5AT compared to BT (p<0.001). Compared to BT, at 120AT the maximum eye temperature remained elevated (p<0.001) and plasma cortisol concentration decreased (p<0.001). The study indicated significant weak correlations (r=0.220; p<0.001) between both measurements at all time points. The results support the use of IRT technique to monitor the response of horses to stress, potentially improving animal management and welfare.
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Bibliography


Becker-Birck M, Schmidt A, Lasarzik J, Aurich J, Mostl E, Aurich C (2013) Cortisol release and heart rate variability in sport horses partici-pating in equestrian competitions. J Vet Behav 8: 87-94.
Cayado P, Munoz-Escassi B, Dominguez C, Manley W, Olabarri B, Sanchez de la Muela M, Castejon F, Maranon G, Vara E (2006) Hor-mone response to training and competition in athletic horses. Equine Vet J Suppl 36: 274-78.
Christensen JW, Beekmans M, van Dalumb M, Van Dierendonck M (2014) Effects of hyperflexion on acute stress responses in ridden dres-sage horses. Physiol Behav 128: 39-45.
Cook N, Schaefer A, Warren L, Burwash L, Anderson M, Baron V (2001) Adrenocortical and metabolic responses to ACTH injection in horses: an assessment by salivary cortisol and infrared thermography of the eye. Can J Anim Sci 81: 621.
Fazio E, Calabrò G, Medica P, Messineo C, Ferlazzo A (2006) Serum cortisol levels of quarter horses: circadian variations and effects of training and western riding events. In: Lindner A (ed) Management of Lameness Causes in Sport Horses. Wageningen Academic Publishers, 2006, Cambridge, pp 175-179.
Fazio E, Medica P, Cravana C, Ferlazzo A (2008) Effects of competition experience and transportation on the adrenocortical and thyroid re-sponses of horses. Vet Rec 163: 713-716.
Irvine CH, Alexander SL (1994) Factors affecting the circadian rhythm in plasma cortisol concentrations in the horse. Domest Anim Endocrinol 11: 227-238.
Kędzierski W, Cywińska A, Strzelec K, Kowalik S (2014) Changes in salivary and plasma cortisol levels in Purebred Arabian horses during race training session. Anim Sci J 85: 313-317.
Mormède P, Andanson S, Aupérin B, Beerda B, Guémené D, Malmkvist J, Manteca X, Manteuffel G, Prunet P, van Reenen CG, Richard S, Veissier I (2007) Exploration of the hypothalamic-pituitary-adrenal function as a tool to evaluate animal welfare. Physiol Behav 92: 317-339.
National Research Council (2007) Nutrient requirements of horses, 6th ed., National Academy Press, Washington DC.
Redaelli V, Luzi F, Mazzola S, Bariffi GD, Zappaterra M, Nanni Costa L, Padalino B (2019) The use of infrared thermography (IRT) as stress indicator in horses trained for endurance: a pilot study. Anim 9: 84.
Schmidt A, Aurich J, Möstl E, Müller J, Aurich C (2010) Changes in cortisol release and heart rate and heart rate variability during the initial training of 3-year-old sport horses. Horm Behav 58: 628-636.
Soroko M, Howell K, Dudek K, Henklewski R, Zielińska P (2017) The influence of breed, age, gender, training level and ambient temperature on forelimb and back temperature in racehorses. Anim Sci J 88: 347-355.
Soroko M, Howell K, Zwyrzykowska A, Dudek K, Zielińska P, Kupczyński R (2016) Maximum eye temperature in the assessment of train-ing in racehorses: correlations with salivary cortisol concentration, rectal temperature and heart rate. J Equine Vet Sci 45: 39-45.
Soroko M, Spitalniak-Bajerska K, Zaborski D, Pozniak B, Dudek K, Janczarek I (2019) Exercise-induced changes in skin temperature and blood parameters in horses. Arch Anim Breed 62: 205-213.
Stewart M, Webster JR, Schaefer AL, Cook NJ, Scott SL (2005) Infrared thermography as a non-invasive tool to study animal welfare. Anim Welf 14: 319-325.
Stewart M, Webster JR, Verkerk GA, Schaefer AL, Colyn JJ, Stafford KJ (2007) Non-invasive measurement of stress in dairy cows using infrared thermography. Physiol Behav 92: 520-525.
Valera M, Bartolomé E, Sánchez MJ, Molina A, Cook N, Schaefer A (2012) Changes in eye temperature and stress assessment in horses during show jumping competitions. J Equine Vet Sci 32: 827-830.
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Authors and Affiliations

M. Soroko
1
K. Howell
2
K. Dudek
3
A. Waliczek
4
P. Micek
4
J. Flaga
4

  1. Institute of Animal Breeding, Wroclaw University of Environmental and Life Sciences, Chelmonskiego 38C, 51-630 Wroclaw, Poland
  2. Microvascular Diagnostics, Institute of Immunity and Transplantation, Royal Free Hospital, Pond Street, London NW3 2QG, UK
  3. Faculty of Mechanical Engineering, Wroclaw University of Technology, Lukasiewicza 7/9, 50-231 Wroclaw, Poland
  4. Department of Animal Nutrition and Biotechnology, and Fisheries, University of Agriculture in Krakow, Al. Mickiewicza 24/28, 30-059 Krakow, Poland

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